Intervertebral spacer

Abstract

An intervertebral spacer is to be inserted between two vertebral bodies. The intervertebral spacer including a pair of block bodies. Each of the block bodies has an abdominal side portion to be directed to an abdominal side of a patient when inserted in the vertebral bodies and a back side portion to be directed to a back side of the patient when inserted in the vertebral bodies. Each block body is configured such that a width of the abdominal side portion is greater than a width of the back side portion.

1 . An intervertebral spacer to be inserted between two vertebral bodies, comprising a pair of block bodies, each of the block bodies having an abdominal side portion to be directed to an abdominal side of a patient when inserted in the vertebral bodies and a back side portion to be directed to a back side of the patient when inserted in the vertebral bodies, each of the block bodies being configured such that a width of the abdominal side portion is greater than a width of the back side portion.  
   
   
       2 . The intervertebral spacer according to  claim 1 , wherein each of the block bodies is configured such that one side surface is a planar surface having substantially no step, and the other side surface is formed with at least one step.  
   
   
       3 . The intervertebral spacer according to  claim 2 , wherein there is only one step on the other side surface of each of the block bodies at a position where the abdominal side portion and the back side portion are connected, the width of the abdominal side portion being substantially constant, the width of the back side portion being substantially constant.  
   
   
       4 . The intervertebral spacer according to  claim 3 , wherein a ratio W 2 /W 1  of the width W 2  of the back side portion to the width W 1  of the abdominal side portion is within a range of 0.4 to 0.8.  
   
   
       5 . The intervertebral spacer according to  claim 1 , wherein each of the block bodies is configured such that one side surface is convex surface having substantially no step, and the other side surface is formed with at least one step.  
   
   
       6 . The intervertebral spacer according to  claim 1 , wherein each of two opposing side surfaces of each of the block bodies is formed with at least one step.  
   
   
       7 . The intervertebral spacer according to  claim 1 , wherein a ratio L 2 /L 3  of a length L 2  of the back side portion to a length L 1  of each of the block bodies is within a range of 0.4 to 0.8.  
   
   
       8 . The intervertebral spacer according to  claim 2  wherein the two block bodies are arranged when inserted in the intervertebral area with the side surfaces being faced each other.  
   
   
       9 . The intervertebral spacer according to  claim 8 , wherein the two block bodies have symmetrical shapes.  
   
   
       10 . The intervertebral spacer according to  claim 9 , wherein the pair of the block bodies are inserted between the two vertebral bodies such that the one side surfaces thereof face each other.  
   
   
       11 . The intervertebral spacer according to  claim 9 , wherein the pair of the block bodies are inserted between the two vertebral bodies such that the other side surfaces thereof face each other.  
   
   
       12 . The intervertebral spacer according to  claim 1 , wherein each of the block bodies include a portion whose height gradually decreases from the abdominal side end of the portion toward the back side end of the portion.  
   
   
       13 . The intervertebral spacer according to  claim 1 , wherein at least one of a top surface and bottom surface of each of the block bodies is a convex surface.  
   
   
       14 . The intervertebral spacer according to  claim 1 , wherein each of the block bodies is configured such that corners thereof have rounded shapes.  
   
   
       15 . The intervertebral spacer according to  claim 1 , wherein a pair of grooves are formed on opposing side surfaces at opposing positions, the grooves being formed to extend in the vertical direction in a condition where said block body is inserted between the vertebral bodies.  
   
   
       16 . The intervertebral spacer according to  claim 1 , wherein a porosity of each of the block bodies is within a range of 0% to 60%.  
   
   
       17 . The intervertebral spacer according to  claim 1 , wherein primary material of the block bodies is ceramic material.  
   
   
       18 . The intervertebral spacer according to  claim 17 , wherein the ceramic material includes calcium phosphate compound.  
   
   
       19 . The intervertebral spacer according to  claim 18 , wherein the calcium phosphate compound has a Ca/P ratio within a range of 1.0 to 2.0.  
   
   
       20 . The intervertebral spacer according to  claim 19 , wherein the calcium phosphate compound comprises hydroxyapatite.  
   
   
       21 . The intervertebral spacer according to  claim 1 , wherein a filler is filled in a space defined by the pair of block bodies and the vertebral bodies.  
   
   
       22 . The intervertebral spacer according to  claim 21 , wherein the filler is a transplantation bone.  
   
   
       23 . The intervertebral spacer according to  claim 1 , wherein each block body has a position having a maximum height between the abdominal side end and the back side end, the height of the each block body gradually decreasing from the position having the maximum height toward the abdominal side end and toward the back side end.  
   
   
       24 . An intervertebral spacer to be inserted between two vertebral bodies, comprising a pair of block bodies, each block body having at least one step formed on at least one of side surfaces thereof, each of the block bodies being divided into a first portion and a second portion by the step.  
   
   
       25 . The intervertebral spacer according to  claim 24 , wherein a width of the first portion is greater than a width of the second portion.  
   
   
       26 . An intervertebral spacer system having a plurality of intervertebral spacers each of which is to be inserted between two vertebral bodies, each of the intervertebral spacers comprising a pair of block bodies having a predetermined length, different block bodies of different intervertebral spacers having different lengths, each of the block bodies having an abdominal side portion to be directed to an abdominal side of a patient when inserted between the vertebral bodies and a back side portion to be directed to a back side of the patient, each of the block bodies being configured such that a width of the abdominal side portion is greater than a width of the back side portion.